Muffler



May 7, 1929. F. F. HAMILTON MUFFLER Filed March 15 IN VENTOE",

Attorney Patented May 7, 1929.

UNITED STATES FRANCIS F. HAMILTON, OF INDIANAPOLIS, INDIANA.

MUFFLER.

Application filed March 15, 1928. Serial No. 261,752.

This invention relates to means for muffling the noise of gases exhausted from gas engines and the like and has for its primary purpose not only the mufiling of the sound but also the prevention of back pressure of the exhaust gases.

The invention is described in reference to the {accompanying drawing, in which 4 .Fig. 1 is a fragmentary top plan view of one form of a muffler embodying my invention' Fig. 2, a fragmentary top plan view of a modified form of the intake end of the muffler; and

Fig. 3, a transverse vertical section through the mufller on the line 33 in Fi 1.

iike characters of reference indicate like parts throughout the several views in the drawing.

I form an outer housing 5 having a transverse cross section preferably of an irregular curved shape as shown in Fig. 3. The intake end of the housing 5 is closed by a head 6 which is curved or bulged outwardly from its outer edges from the housing end, and thence sharply inwardly toward a point decidedly to one side away from the central axis of the housing, and an intake pipe 7 is entered through the head 6 at this point to extend for a substantial length therein, a tight joint being made between the head 6 and the pipe 7.

Within the housing 5 is positioned an ex pansion chamber 8 similar in shape to the housing 5 but having a smaller volume so that there is a continuous space around and between the chamber 8 and the housing 5 of substantially the same width throughout.

This chamber 8 is spaced inwardly from the head 6 so that there is a space defined between the forward flat end 9 of the chamber 8 and the curved head 6, which space is in communication around the edges of the end 9 with the longitudinal circumferential space between the chamber 8 and the housin 5.

The pipe 7 extends to within the chamber 8 for a substantial distance as indicated in Fig. 1. The opposite or rear end of the chamber 8 has an outwardly bulged head 10 which has an inner concave face presented inwardly against which the gases discharged from the end of the pipe 7 are directed. The center of curvature of the inner face lies upon the axial center line of the pipe 7 substantially at its discharging end or just to the rear of the end.

The chamber 8 is made gas tight throughout and to permit the gases to escape therefrom, a plurality'of holes 11 are formed through the forward head 9 immediately around the pipe 7, Fig. 3, the total area of all the holes 11 being, equal to or greater than that of the cross sectional area of the pipe 7.

By placing the pipe 7 down and off to near one side of the housing 5 and chamber 8, gases discharging from the chamber 8 into the forward space against the housing head 6, and by the aid of the curvature of the head 6, are deflected back around the sides of the chamber 8 along the housing It is obvious that the gas is differentiated or spread out, some taking the shortest path A and some of the longest path B (Figs.

l and 3), all of the gas travelling to the rear of the housing 5 and heat being dissipated from the gases through the Wall of the housing 5.

The gases coming the paths of various lengths are integrated, that is summed up, or collected together behind the rear end of the chamber 8 by the rearwardly extended conical-like housing end 12 which has its apex on 'the extended center line of the pipe 7. A discharge or tail-pipe 13 is fitted to the end 12 at the apex to have its center line coincide with that of the pipe 7. By so positioning the pipe 13 in reference to the pipe 7, gases that go the path B travel a farther distance through the muffler than do the gases travelling the path A and hence the B stream does not arrive until after the A stream has arrived in the pipe 13.

' In some cases I find it advisable to place a layer of material 14:, such as asbestos, around the inner side wall of the chamber 8, which material is retained by the coarse screen 15. By this means, a rough, porous facing is obtained around the chamber wall so that all sound not otherwise broken up and eliminated is thereby absorbed.

Where a cheaper construction is required, the modified form as shown in Fig. 2 is employed, to have a flat housing forward head 16, and to be without a chamber wall sound deadener.

While I have here described my invention in the one precise form as new best known to me, it is obvious that many structural changes may bemade without departing from the spirit of the invention, and I, therefore, do not desire to be limited to the precise structure as shown and described, nor an more than may be necessitated by the foll owing claims.

I claim:

1. In a muffler of exhaust gases, a housing closed at both ends, an expansion chamber within the housing defining a passageway therearound throughout its length between the chamber and the housing, an intake pipe entering the housing and front end of the chamber to have its discharge end within the chamber and directed toward the rear end of the chamber, said intake pipe entrance into said chamber being considerably to one side of the central-most axis of the chamber, said chamber having a discharge opening therefrom at its forward end, and the rear end of said housing having a discharge opening therefrom.

2. In a muflier of exhaust gases, a housing closed at both ends, an expansion chamber within the housing defining a passageway therearound throughout its length between the chamber and the housing, an intake pipe entering the housing and front end of the chamber to have its discharge end within the chamber and directed toward the rear end of the chamber, said intake pipe entrance into said chamber being considerably to one side of the central-most axis of the chamber, said chamber having a discharge opening therefrom at its forward end, and the rear end of said housing having a discharge opening therefrom, and insulating means around said expansion chamber.

3. In a muffler of exhaust gases a housing closed at both ends, an expansion chamber within the housing definin a passageway therearound throughout its length between the chamber and the housing, an intake pipe entering the housing and front end of the chamber, to have its discharge end within the chamber and directed toward the rear end of the chamber, said intake pipe entrance into said chamber being considerably to one side of the central-most axis of the chamber, said chamber having discharge openings therefrom at its forward end, and the rear end of the housing having a discharge opening therefrom, and the rear end of said chamber being concave to have its center of curvature within the chamber substantially on the center line of said intake pipe.

4. In a muffler of exhaust gases, a housing closed at both ends, an expansion chamber within the housing defining a passageway therearound throughout its length between the chamber and the housing, an intake pipe entering the housing and front end of the chamber to have its discharge end within the chamber and directed toward the rear end of the chamber, said intake pipe entrance into said chamber being considerably to one side of the central-most axis of the chamber, said chamber having discharge openings therefrom at its forward end, and the rear end of the housing having a discharge opening therefrom, the rear end of said chamber being concave to have its center of curvature within the chamber substantially on the center line of said intake pipe, and insulating means around said expansion chamber.

5. In a muflier of exhaust gases, a housing closed at its forward end, an expansion chamber within the housing spaced therein to define a space therearound and at its forward end between it and the housing, an intake pipe entering the housing and discharging to within the chamber, a wall of said chamber having a concave face directed toward the discharge end of said intake pipe, the center of curvature of the face being substantially on the center line of the pipe, said chamber having discharge openings therefrom in the wall opposite said concave face whereby gases escaping from the chamber are directed toward the front end of said housing, and a collecting head on the rear end of the housing having a discharge opening therefrom, said discharge opening being on the center line of said intake pipe and said intake pipe entrance being considerably to one side of the central longitudinal axis of said housing and chamber.

6. In a muffler of exhaust gases, a housing closed at its forward end, an expansion chamber within the housing spaced therein to define a space therearound and at its forward end between it and the housing, an intake pipe entering the housing and discharging to within the chamber, a wall of said chamber having a concave face directed toward the discharge end of said intake pipe, the center of curvature of the face being substantially on the center line of the pipe, said chamber havin discharge openings therefrom in the waIl opposite said concave face whereby gases esca ing from the chamber are directed towar the front end of said housing, and a collecting head on the rear end of the housing having a discharge opening therefrom, said discharge opening being on the center line of said intake pipe and said intake pipe entrance being conslderably to one side of the central longitudinal axis of said housing and chamber, and insulating means around said chamber.

7. In a muffler of exhaust gases, a housing closed at its forward end, an expansion chamber within the housing spaced therein to define a space therearound and at its forward end between it and the housing, an intake pipe entering the housing and discharging to within the chamber, a wall of said chamber having a concave face directed toward the discharge end of said intake pipe, the center of curvature of the face being substantially on the center line of the pipe, said chamber having discharge openings therefrom in the Wall opposite said concave face whereby gases escaping from the chamber are directed toward the front end of said housing, and a collecting head on the rear end of the housing having a discharge opening therefrom, said discharge opening being on the center line of said intake pipe and said intake pipe entrance being considerably to one side of the central longitudinal axis of said housing and chamber, said chamber discharge openings being grouped around said intake pipe.

8. I11 a muflie'r of exhaust gases, a housing closed at its forward end, an expansion chamber Within the housing spaced therein to define a space therearound and at its forward end between it and the housing, an intake pipe entering the housing and discharging to within the chamber, a wall of said chamber having a concave face directed toward the discharge end of said intake pipe, the center of, curvature of the face being substantially on the center line of the pipe, said chamber having discharge openings therefrom in the wall opposite said concave face whereby gases escaping from the chamber are directed toward the front end of said housing, and a collecting head on the rear end of the housing having a discharge opening therefrom, said discharge opening being on the center line of said intake pipe and said intake pipe entrance being considerably to one side of the central longitudinal axis of said housing and chamber, said intake pipe projecting a substantial distance into said chamber and said chamber discharge openings being grouped around said intake pi e.

In a mufiler of exhaust gases, a housing closed at its forward end, an expansion chamber within the housing spaced therein to define a space therearound and at its forward end between it and the housing, an intake pipe entering the housing and discharging to Within the chamber, a Wall of said chamber having a concave face directed toward the discharge end of said intake pipe, the center of curvature of the face being substantially on the center line of the pipe, said chamber having discharge openings therefrom in the wall opposite said concave face whereby gases escaping from the chamber are directed toward the front end of said housing, and a collecting head on the rear end of the housing having a discharge opening therefrom, said discharge opening being on the center line of said intake pipe and said intake pipe entrance being considerably to one side of the central longitudinal axis of said housing and chamber, and said housing forward head being formed to deflect gases from the chamber to entirely around the longitudinal passageway between said chamber and saidhousing.

In testimony whereof I affix my signature.

FRANCIS F. HAMILTON. I 

